The present invention relates to an image noise reduction method and apparatus for causing three-dimensional dispersion of noise components of images in the visual space to remove noises from images.
In conventional MRI apparatuses for making a diagnosis on a patient by using nuclear magnetic resonance phenomena, noises are removed from images obtained as a result of diagnosis typically by passing image signals through an analog or digital filter and removing noises from images in that filter.
When the noise removing method using a filter such as the above described prior art is used, however, it is difficult to completely remove image noises and the signal-to-noise ratio of images is lowered. Therefore, there is a limit in obtaining clear images. On the other hand, MRI apparatuses are requested to provide clear images in order to improve the accuracy of diagnosis.
It is well known to obtain a stereoscopic image by juxtaposing on the same plane two sheets of images reconstructed with changed visual points from image data which are measured three-dimensionally by the 3DFT method and observing these images with left and right eyes as described in JP-A-63-290548, for example.
This method is shown in FIG. 1. With respect to an image 43 containing three-dimensional information obtained by using the 3DFT method, respective points of image information seen from each of eyes 41 and 42 are added together to obtain two sheets of images seen from respective visual points. The two sheets of images are juxtaposed on an identical plane and are observed with both eyes brought near the center or through stereo glass. A region to be observed is thus obtained as a stereoscopic image.